CN106190071A - A kind of capsule fiber leak preventive and application thereof - Google Patents

Abstract

The invention provides a capsule fiber anti-leakage agent and an application thereof. The capsule fiber anti-leakage agent includes a capsule, fibers and a fiber dispersant inside the capsule, and the capsule is a water-soluble capsule. The present invention can be applied to the cement slurry used for well cementing. The capsule fiber anti-leakage agent can be uniformly dispersed in the cement slurry, and the cement slurry can be kept stable; the cement slurry prepared by using the fiber anti-leakage agent of the embodiment of the present invention It can seal 1-3mm cracks and has good leak-proof performance. The fiber anti-leakage agent of the invention can be applied to cement slurry systems of various densities, has strong compatibility with various admixture systems, and does not affect the performance of the cement slurry.

Description

A kind of capsule fiber anti-leakage agent and its application

technical field

The invention belongs to the field of cement admixtures, in particular to a capsule fiber anti-leakage agent and its application.

Background technique

In oil and gas well cementing operations and other underground cementing operations, it is usually required to inject cement slurry containing cement, water and admixtures into the predetermined formation underground through surface pumping equipment to seal the annulus between the formation and the casing . Typically cement slurry is pumped into the casing and returns to the annulus through the gap between the casing and the formation. The cement slurry solidifies in the annulus to form a hard cement sheath, which can form a bond with the formation and the casing, that is, well cementing.

Lost circulation is the phenomenon that various working fluids (including drilling fluid, cement slurry, completion fluid and other fluids, etc.) leak into the formation under the action of pressure difference during various downhole operations such as drilling, cementing, and testing. Once leakage occurs in an oil and gas well, it will not only delay the drilling operation time, prolong the drilling cycle, lose drilling fluid, damage oil and gas layers, interfere with geological logging work, but also may cause a series of complex situations and accidents such as well collapse, pipe sticking, blowout, etc., and even The wellbore will be scrapped, causing significant economic losses; in addition, lost circulation will also interfere with the normal maintenance and treatment of geological logging work and drilling fluid performance. Therefore, the occurrence of lost circulation should be avoided as much as possible during drilling operations. The lost circulation problem is a technical problem that has existed for a long time in drilling work and has not been well solved. Therefore, the plugging technology is an important subject of long-term research in the drilling engineering field. In recent years, leakage plugging technology has developed greatly. All oilfields and regions at home and abroad have summed up plugging technology suitable for the characteristics of the region. The variety of plugging materials is also increasing, and the success rate of plugging is also increasing. . Nevertheless, due to the complex causes of lost circulation, many restrictive factors, and the strong pertinence of plugging technology, the problem of lost circulation has not been well solved so far, and the losses caused by lost circulation are still high.

At present, the anti-leakage agent commonly used in well cementing has poor dispersion in cement slurry and is easy to float up. It is unevenly dispersed in cement slurry, which is easy to cause cement slurry to agglomerate, and is easy to cause bridge plugging and suffocation in the annulus between the formation and the casing. Pump site, causing safety accidents, poor leak-proof performance.

Contents of the invention

In view of the above problems in the prior art, the main purpose of the present invention is to provide a capsule fiber anti-leakage agent and its application, which can be applied to cement slurry for well cementing, and the capsule fiber anti-leakage agent is added to the cement slurry It can be evenly dispersed in the medium, and the cement slurry can be kept stable, and the leakage prevention ability is strong.

In order to achieve the above object, the present invention adopts the following technical solution: a capsule fiber leak-proof agent, comprising a capsule, fiber and fiber dispersant inside the capsule, and the capsule is a water-soluble capsule.

As a further preference, each capsule contains 1-2 parts of high-strength inorganic fiber and 1-2 parts of fiber dispersant.

As a further preference, the covering length of the capsule is 12-14mm.

As a further preference, the fibers are bundled high-strength inorganic fibers,

As a further preference, the high-strength inorganic fibers are selected from carbon fibers, boron fibers, silicon nitride fibers, glass fibers and ceramic fibers.

As a further preference, the high-strength inorganic fibers have a length of 5-6 mm and a diameter of 10-30 μm.

As a further preference, each portion of the capsule contains two portions of high-strength inorganic fibers, one portion of fiber length is 5 mm, and the portion length of fiber is 6 mm.

As a further preference, the fiber dispersant is selected from sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate.

An application of a capsule fiber anti-leakage agent, the capsule fiber anti-leakage agent is added to cement slurry used for well cementing.

As a further preference, the capsule fiber anti-leakage agent is dry-mixed when added to the cement slurry used for well cementing.

As a further preference, the amount of the capsule fiber anti-leakage agent added to the cement slurry used for well cementing is 0.5-1.5% (BWOC).

The beneficial effects of the present invention are as follows:

(1) The capsule fiber leak-proof agent of the present invention is formed by adding fiber and fiber dispersant to the capsule; wherein, after the capsule is mixed into the cement slurry, it dissolves rapidly when it meets water and is stirred, and releases The fiber and fiber dispersant contained in it; when the capsule is dissolved, the fiber is quickly dispersed into a single fiber to form a fiber network, which improves the leakage prevention ability of cement slurry; the fiber dispersant can make the fiber material evenly and randomly dispersed In the cement slurry, it does not affect other properties of the cement slurry, such as the rheological properties of the cement slurry, which can ensure safe construction.

(2) Since the fibers are easy to agglomerate and cannot be dry-mixed, it is not conducive to on-site construction. However, in the present invention, high-strength inorganic fibers are arranged in the capsules, and the capsules can be dry-mixed after being mixed into the cement slurry, thus solving the problem of fiber The problem that similar anti-leakage agents cannot be dry-mixed on site greatly facilitates on-site construction.

(3) In the case where dry mixing is not possible, the on-site cementing operation can only be carried out from the top of the cementing truck into the mixing grout, and the amount of addition is difficult to control. If the amount is too much, "cement lumps" may be formed. , resulting in safety accidents; if the dosage is small, it is difficult to guarantee the plugging effect and improve the mechanical properties of cement stone. However, the present invention can be dry mixed, and can also accurately control the addition amount.

(4) The present invention adopts bundle-shaped high-strength inorganic fibers, which are conveniently added into capsules, have high tensile strength, high pressure-bearing capacity, and good leak-proof effect.

(5) The fiber anti-leakage agent of the present invention can be applied to cement slurry systems of various densities, and has good compatibility with various admixtures.

detailed description

Aiming at the defects of the anti-leakage agent in the prior art, the present invention provides a capsule fiber anti-leakage agent and its application, which can be added to the cement slurry used for cementing, and the capsule fiber anti-leakage agent is added to the cement slurry It can be evenly dispersed in the medium, and the cement slurry can be kept stable, and the leakage prevention ability is strong. The problem of uneven dispersion, easy agglomeration and poor leak-proof effect when the existing anti-leakage agent is applied in cement slurry is solved.

The capsule fiber leak-proof agent of the embodiment of the present invention includes a capsule, fiber and fiber dispersant inside the capsule, and the capsule is a water-soluble capsule.

Each capsule of the present invention contains 1-2 parts of fiber and 1-2 parts of fiber dispersant. The ratio of the number of fibers in the capsules of the embodiment of the present invention to the fiber dispersant is determined according to the dispersibility of the fibers, and the dosage of the capsules is determined according to the plugging effect of the test. The covering length of the capsule is 12-14mm. The fiber dispersant described in the embodiment of the present invention is selected from sodium tripolyphosphate, sodium hexametaphosphate or sodium pyrophosphate.

The fiber described in the embodiment of the present invention is a high-strength inorganic fiber, and the high-strength inorganic fiber is selected from carbon fiber, boron fiber, silicon nitride fiber, glass fiber and ceramic fiber. The high-strength inorganic fiber of the present invention can be processed into bundles and conveniently added into capsules, while other non-inorganic fibers cannot be added into capsules because they are easy to form agglomerates. In addition, the embodiment of the present invention can also carry out hydrophilic treatment on the surface of the high-strength inorganic fiber, so that it is easier to disperse in the cement slurry.

Different lengths of fiber anti-leakage agents have different plugging properties. It is more effective to use long fibers when plugging large-sized pores or gaps. In the case that both short fibers and long fibers can achieve plugging, the use of short fibers Leakage is smaller. Currently, the fiber lengths commonly available on the market are generally 3mm, 5mm, 6mm, 9mm, 12mm, etc. When the fiber length is 3mm, the leak-proof ability is poor. When the fiber length is 9mm and 12mm, it is easy to block the cementing tool and cause safety accidents. The ideal fiber length in the embodiment of the invention is 5-6 mm, and the diameter is 10-30 μm.

The capsule fiber anti-leakage agent of the embodiment of the present invention can be added to the cement slurry used for well cementing, and the capsule fiber anti-leakage agent can be dry-mixed when added to the cement slurry used for well cementing. When the plugging crack is large, the dosage of the capsules in the embodiment of the present invention is higher, and when the crack is smaller, the dosage of the capsule is smaller, which is determined by the plugging effect of the plugging test.

In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation manners.

Example 1

Take 10 parts of bundled carbon fiber with a fiber length of 6mm, put them into 10 parts of 5# capsules respectively, each capsule contains 1 part of bundled carbon fiber, and then add 1 part of fiber dispersant sodium tripolyphosphate to each capsule to form Capsule fibers are leak-proof. Example 1 of the present invention capsule fiber anti-leakage agent is coded as J01, and it is evaluated for its anti-leakage performance, and the results are shown in Table 1.

Table 1 J01 leak-proof performance evaluation

Example 2

Get 20 parts of bundled glass fiber, fiber length is 5mm, put into 10 parts of 4# capsules, contain 2 parts of bundled glass fiber in every part of capsule, then add 2 parts of fiber dispersant sodium hexametaphosphate in every part of capsule, Forms a capsule fiber that is leak-proof.

Example 2 of the present invention uses J02 as the code name of the capsule fiber leak-proof agent to evaluate its leak-proof performance, and the results are shown in Table 2.

Table 2 J02 leak-proof performance evaluation

Example 3

Take 10 parts of bundle-shaped ceramic fiber, put them into 10 parts of 5# capsules, each capsule contains 1 part of bundle-shaped carbon fiber, 5 parts of fiber length are 5mm, and the other 5 parts of fiber length are 6mm, and then each capsule Add 1 part of fiber dispersant sodium pyrophosphate to form capsule fiber leak-proof. Example 3 of the present invention capsule fiber anti-leakage agent is coded as J03, and its anti-leakage performance is evaluated, and the results are shown in Table 3.

Table 3 J03 leak-proof performance evaluation

Example 4

Get 20 parts of bundled silicon nitride fiber, put it into 10 parts of 4# capsules, each capsule contains a bundled silicon nitride fiber with a fiber length of 5mm and a bundled silicon nitride fiber with a fiber length of 6mm Fiber, then add 1 part of fiber dispersant sodium hexametaphosphate in each capsule to form a leak-proof capsule fiber.

Example 4 of the present invention uses J04 as the code name of the capsule fiber leak-proof agent to evaluate its leak-proof performance, and the results are shown in Table 4.

Table 4 J04 leak-proof performance evaluation

Example 5

Take 10 parts of bundled glass fiber (fiber length is 5mm) and 10 parts of bundled carbon fiber (fiber length is 5mm), put them into 10 parts of 4# capsules, each capsule contains 1 part of bundled glass fiber and 1 part of carbon fiber , and then add 2 parts of fiber dispersant sodium hexametaphosphate to each capsule to form a leak-proof capsule fiber.

Example 5 of the present invention capsule fiber anti-leakage agent is coded as J05, and its anti-leakage performance is evaluated, and the results are shown in Table 5.

Table 5 J05 leak-proof performance evaluation

Example 6

Take 10 parts of bundled glass fiber (fiber length is 5mm) and 10 parts of bundled carbon fiber (fiber length is 6mm), put them into 10 parts of 4# capsules, each capsule contains 1 part of bundled glass fiber and 1 part of carbon fiber , and then add 2 parts of fiber dispersant sodium hexametaphosphate to each capsule to form a leak-proof capsule fiber.

Example 6 of the present invention capsule fiber leak-proof agent with J06 as the code name, its leak-proof performance evaluation, the results are shown in Table 6.

Table 6 J06 leak-proof performance evaluation

Example 7

Get 10 parts of bundled boron fiber (fiber length is 5mm) and 10 parts of bundled carbon fiber (fiber length is 6mm), put into 10 parts of 4# capsules, each capsule contains 1 part of bundled boron fiber and 1 part of carbon fiber , and then add 2 parts of fiber dispersant sodium hexametaphosphate to each capsule to form a leak-proof capsule fiber.

Example 7 of the present invention, the capsule fiber leak-proof agent is coded as J07, and its leak-proof performance is evaluated, and the results are shown in Table 7.

Table 7 J07 leak-proof performance evaluation

Example 8

Take 10 parts of bundled boron fiber, the fiber length is 6mm, put them into 10 parts of 5# capsules respectively, each capsule contains 1 part of bundled boron fiber, and then add 1 part of fiber dispersant sodium tripolyphosphate in each capsule , forming a capsule fiber leak-proof. Example 8 of the present invention capsule fiber leak-proof agent with J08 as the code name, its leak-proof performance evaluation, the results are shown in Table 1.

Table 8 J08 leak-proof performance evaluation

As can be seen from the leak-proof performance evaluation table of Examples 1-8 of the fiber leak-proof agent of the present invention, the fiber leak-proof agent of Example 1-8 of the invention can realize rapid and good plugging effect, and increase the size of the capsule or fiber Dosage can block larger pores or gaps. And has a high pressure bearing capacity, the pressure bearing capacity can reach more than 3.5MPa.

By adding the anti-leakage agent of Examples 1-8 of the present invention into the cement slurry and stirring evenly, the rheology of the experimental slurry was tested at 50° C. with a viscometer. The results show that the rheological properties of the cement paste are not affected after adding the fiber anti-leakage agent, and it has good compatibility.

The above-mentioned technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

(1) The capsule fiber leak-proof agent of the present invention is formed by adding fiber and fiber dispersant to the capsule; wherein, after the capsule is mixed into the cement slurry, it dissolves rapidly when it meets water and is stirred, and releases The fiber and fiber dispersant contained in it; when the capsule is dissolved, the fiber is quickly dispersed into a single fiber to form a fiber network, which improves the leakage prevention ability of cement slurry; the fiber dispersant can make the fiber material evenly and randomly dispersed In the cement slurry, it does not affect other properties of the cement slurry, such as the rheological properties of the cement slurry, which can ensure safe construction.

(2) Since the fibers are easy to agglomerate, they cannot be dry-mixed, which is not conducive to on-site construction. However, the present invention arranges high-strength inorganic fibers in the capsule, and the capsule can be dry-mixed after being mixed into the cement slurry without agglomeration , thus solving the problem that the fiber-based anti-leakage agent cannot be dry-mixed on site, which greatly facilitates on-site construction.

(3) In the case where dry mixing is not possible, the on-site cementing operation can only be carried out from the top of the cementing truck into the mixing grout, and the amount of addition is difficult to control. If the amount is too much, "cement lumps" may be formed. , resulting in safety accidents; if the dosage is small, it is difficult to guarantee the plugging effect and improve the mechanical properties of cement stone. However, the present invention can be dry mixed, and can also accurately control the addition amount.

(4) The present invention adopts bundle-shaped high-strength inorganic fibers, which are conveniently added into capsules, have high tensile strength, high pressure-bearing capacity, and good leak-proof effect.

(5) The fiber anti-leakage agent of the present invention can be applied to cement slurry systems of various densities, and has good compatibility with various admixtures.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (9)

1. A capsule fiber leak-proof agent, characterized in that: it comprises a capsule and fiber and a fiber dispersant positioned inside the capsule, and the capsule is a water-soluble capsule. 2. The anti-leakage agent for capsule fiber according to claim 1, characterized in that: each part of the capsule contains 1-2 parts of high-strength inorganic fiber and 1-2 parts of fiber dispersant. 3. The capsule fiber leak-proof agent according to claim 1 or 2, characterized in that: the length of the capsule is 12-14mm. 4. The anti-leakage agent for capsule fibers according to claim 1, characterized in that: the fibers are bundle-shaped high-strength inorganic fibers. 5. The anti-leakage agent for capsule fiber according to claim 4, characterized in that: the high-strength inorganic fiber is selected from carbon fiber, boron fiber, silicon nitride fiber, glass fiber and ceramic fiber. 6. The anti-leakage agent for capsule fiber according to claim 4, characterized in that: the length of the high-strength inorganic fiber is 5-6 mm, and the diameter is 10-30 μm. 7. The anti-leakage agent for capsule fiber according to claim 1, characterized in that: the fiber dispersant is selected from sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate. 8. The application of the capsule fiber anti-leakage agent according to any one of claims 1-7, characterized in that: the capsule fiber anti-leakage agent is added to the cement slurry used for well cementing. 9. The capsule fiber anti-leakage agent according to claim 8, characterized in that: the capsule fiber anti-leakage agent is dry-mixed when added to the cement slurry used for well cementing.